Apple Adjustable Keyboard

Model Number: M1242
FCC ID ; BCGM1242
ALPS Low Profile Clicky switch.
Introduced to the market in 1993


Mine was modified with oily grease 
around stems and  click leaf to dampen clicking sound

 

You can find many pages introducing Apple Adjustable keyboard.  Please refer following pages for detailed review and high quality pictures . 
   Wikipedia    TidBIT    Keyboard Maniacs_annother side    Apple keyboard collection    S.D's Macintosh site

 

 

 
     Please note that a metal spring is used to lock
     legs in up-right position.
      I don't have any Mac system and do not know
       how to use these tact switches.. 

ALPS Low Profile Switch

Switches used in this board is described as SKFS/clicky  in ALPS catalog  '94 edition.

But mine doesn't click at all but gives firm tactile feedbacks.

In famous MouseFan page,  the author says his adjustable has clicky sound
By what reason,  mine had been lubricated with oily grease all around stems, inside switching assemblies including click( tactile ) leaves.   Because I didn't know if mine had been initially lubricated by factory or ex-owner had done it,  I didn't want to make this Adjustable page for long.  But it's not that bad to examine ALPS Low Profile Switch.

U.S Patent 4935591 is very close to this switch. but Figs in this patent paper are bit different from  this switch.  You can see 
patent 4935591 here

 
Here is mine.

 You may notice grease pasted around stems. 

Close up of a stem

 

not a little bit of grease, but  a lot of grease used around a stem, click leaf, coiled spring and inner walls of upper housing.

You can use a hand made Cherry MX tool for disassembling upper housing of this Low Profile Switch.


    Inner construction and parts
 A cupper belt seen in upper section is a built-in jumper.
 Bellow the jumper, you can see a click leaf ( tactile leaf
  in this case)  
 Viewing from opposite angle.
 
 Switching assembly is similar with what can be seen in U.S patent
 4935591 as noted above. 
Some may feel this switching construction resembles those used in  Simplified-I.

But there are big differences between this one and simplified-I.

1. Movable switching leaf with two arms is placed close to a wall
    ( outer side ) and non-movable  plate  is placed close to a stem.

2. Both leaf and plate are tightly held within slits in a lower
    base assembly.
    Those switching plates in Simplified-I are just loosely sit in a
    base assembly and are kept upright position in separated
    rooms in upper housing. For easy assembling of a switch, there
    are excessive space in an upper housing for switching plates.   
   

                  This side meets a Click( tactile ) leaf.

  This side meets a switching leaf. Two projections at both side
   push switching leaf and open contacts at up most position of
   a stem.
 Click leaf.
 The bumps at the both end make clicking sound.
 I think upper portion of arms at both ends hit a jumper too. 
 
 This side faces to a stem.
 You can see two stabilizing bends in about 80 degrees at the
 bottom den of the plate. 

 Upper housing from top

Upper housing;  inner view

Is this board clicky or tactile ?
After removing oily grease from a stem, leaf spring, inner walls around a jumper plate in the lower housing, this switch actually generate slicking sound.  But it's impossible to remove all grease from inner assemblies. removing/assembling click leaf is tad difficult compared to real-complicated Bigfoot class ALPS.   I don't want to do this cleaning for all switches on this board.

  Apple used tactile alps switches for their mechanical keyboards like M0115, M0116, GS-II board and extended II with rubber damper.  In order to produce this board with complicated adjustable mechanism,  Apple might use ALPS Low Profile switch in order to save total height of this keyboard.  While in ALPS low profile line, ALPS had only two variations, one was clicky ( model number SKFS  ) and the other was linear ( model number SKFR  )*1.  For this board,  Apple chose clicky version by what reason。Mine might be modified with grease by ex-owner to decrease cliking sound. 

 

Looks COOL!   want a NIB one with palm rests.

By the way........

Don't you think  this NEC switch looks like to ALPS Low Profile ?    You can see this switch  here

 *1; there is an another variation of ALPS low profile linear switch.  Older type can be seen in IBM Multistation keyboard P/N 5962851  and Toshiba Laptop J3100GT (  sold as T5200 in US&EMEA ) 

Edited and uploaded; Feb.23.2009
By Sandy. 

 

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